The present invention relates generally to systems and methods of visual orientation.
Systems for observing an area of interest are known in the art. They typically are located on a moving vehicle, such as an airplane, or they are stationary on the land, and they are utilized to view the nearby terrain and to determine the details of objects within the area of interest.
For example, it may be desired to find all of the trees in a plantation which have a certain disease. This example utilizes a viewing system on an airplane which flies over the plantation of trees. The user first views the plantation with a wide field of view, enabling him to get a feel for the layout of the plantation and to know his current global position with respect to the plantation. However, in order to view the marks of the disease and thereby to find the diseased trees, the user typically has to zoom in on each tree. In the zoomed resolution, while the user can see the details of any tree much better, the field of view is much smaller and therefore, it is extremely difficult to maintain one""s xe2x80x9corientationxe2x80x9d or a global sense of where one is looking. Certainly, if the user keeps the observing system in the zoomed state and, in that state, moves the system to view other trees, the user will eventually not know where within the plantation of trees he is and, furthermore, will be unable to know whether the diseased tree he is currently viewing is one he has viewed previously. In order to regain a feel for his location, the user has to return to the non-zoomed state.
In prior art observation systems, there is a conflict between a viewer""s need to know, globally, where he is looking and his need to view the area of interest in detail.
U.S. Pat. No. 5,155,774 describes an observation system which attempts to provide users with position information regarding the objects within a field of view. To do so, the system of ""774 compares a detailed map with the current image of the observation system. The objects of the map are correlated with the objects of the image, thereby to determine which objects are being viewed.
However, if the terrain being viewed has changed since the map was created, the system of ""774 does not work. Furthermore, it does not help a user to orient himself within the situation of the plantation of trees as described hereinabove, since few maps have details of such a plantation.
It is an object of the present invention to provide an orientation system by which the user can maintain his overall knowledge of a global area being searched while viewing only a small portion of the area being searched.
In accordance with the present invention, the orientation system first views the area being searched with a wide field of view (FOV). This produces a reference image of the global area to search. The reference image is displayed on a viewing screen while the orientation system is zoomed towards an area of interest. The current field of view of the orientation system is noted, typically by a frame, on the continually displayed reference image. As the user moves the zoomed orientation system around the searching area, the frame of the current field of view moves around the reference image. Thus, the user can continually know where, within the global searching area shown in the reference image, the narrow field of view which he is viewing is.
Furthermore, when a user wants to remember an object, e.g. for example one of the diseased trees in the plantation, he can mark the tree in the zoomed image. The mark will also be displayed on the reference image. Thus, the present system enables the user to know where, in the global searching area, the object of interest is located. If the user passes an area previously searched, the previously found objects in that area will be noted with marks. Thus, the user can always tell which objects he has previously seen.
There is therefore provided, in accordance with a preferred embodiment of the present invention, a system and method for providing visual orientation to a user. The system includes a reference memory, a camera, a transformation unit and a display unit. The method steps are performed by the elements of the system.
In accordance with a preferred embodiment of the present invention, the reference memory stores a wide field of view (FOV) reference image of a searching area, whether generated from the camera or externally. The camera produces images of portions of the searching area with FOVs of not greater than the wide FOV. The transformation unit generates transformations between each of the zoomed images and the reference image. The display unit displays both the reference image and a current image of a portion of the scene and also displays, on the reference image, a frame indicating where, within the scene, the camera is currently viewing.
Additionally, in accordance with a preferred embodiment of the present invention, the display unit includes a unit for indicating an object of interest and a unit for displaying a mark in at least the reference image indicating the location of the object of interest.
Furthermore, in accordance with a preferred embodiment of the present invention, the transformation unit includes a unit for utilizing previous transformations to determine the current transformation. Alternatively, the transformation unit includes a unit for utilizing external camera information and for utilizing previous transformations to determine the current transformation.
Still further, in accordance with a preferred embodiment of the present invention, the unit for displaying a mark includes a unit for displaying the mark additionally in the current zoomed image if the current zoomed image views a portion of the reference image in which an object has already been marked.
Additionally, in accordance with one embodiment of the present invention, the camera is movable. Alternatively, the camera is stationary.
Finally, in accordance with one embodiment of the present invention, the reference image is received from a camera. Alternatively, the reference image is received externally.